One purpose of this work is to determine the parameters of task-unrelated-thought instrusions, TUTs, (daydreaming/mindwandering) as well as related mental activity such as insight and concentration. A second purpose is to investigate the relation between sustained attention and age. The purposes are accomplished through the use of controlled laboratory studies and retrospective questionnaires. Outcomes derived from these purposes and obtained during the reporting year were: (a) age was found to affect the magnitude of the effortful component of the vigilance decrement function with the young and the elderly having similar decay rates and both having larger decay rates than middle-aged; (b) the frequency of TUTs in 6.6 hours recording during 12 vigilance tasks was found to be strongly and inveresely related to age; individuals over 60 years old had 83% fewer TUTs than 17-29 year olds; (c) arousal during vigilance was found to be unrelated to level of extraversion as predicted by one personality theory; (d) men using strategies with aggressive and deliberate involvement in the vigilance task detected more targets than men using passive involvement and concentration strategies. Efforts over the next fiscal year will include an analysis of : (a) 7-10 year longitudinal changes in retrospectively reported daydreaming characteristics, (b) relationships between aspects of sexual activity in women and their level of sexual daydreaming, (c) the time course of TUTs during vigilance, (d) the relation of TUT frequency during vigilance to general retrospective reports of daydreaming, (e) the relation between the attentional demands of a vigilance task and the frequency of TUTs, (f) the relation between success on memory tasks usually requiring "creative" thought generation for high level performance and the frequency of TUTs, and (g) the temporal stability of frequency of TUTs during a laboratory task.